Finding out about and then understanding the forces acting on a moving object, based on a description of the change in motion of this object, is an important part of the conceptual understanding of Newton's law of motion. Using Hempel's deductive-normative model for scientific explanation, we developed a deductive explanation task (DET), and we applied this task in teaching students to improve their knowledge about force and motion. The results showed that many students received benefits and reached a good conceptual understanding by using the DET. Also, many students responded that learning physics through deductive thinking was less difficult, and in fact, this method of learning was even interesting. Based on the research results, we present some recommendations and suggestions for further study for more effective physics teaching.